In recent times, plastic composites have been fabricated into anti-static bags and envelopes. These are utilized to protect sensitive electronic components and chips from electrical charges and static electricity, thus preventing their damage. While various laminates of plastic have been suggested as desirable anti-static composites, most have the drawback that the thin metal conductive layer of the composite tends to abrade or crack. Abrasion is a particularly troublesome problem, since it not only diminishes the effectiveness of the bag or envelope in protecting the components, but the "flaking" or "crumbing" of the metal forms a contaminate. These contaminates can damage rather than protect the electronic components contained in the envelopes.
Usually several layers of plastic are used to form these anti-static envelopes in order to add mechanical strength and durability to the package. However, most packages are vulnerable to breakdown of their protective metal layer.
Where plastic composites have been impregnated with carbon to provide a conductive property, they have been found to lack mechanical strength. Such layers are usually bonded to another layer by an aluminum paste adhesive, as taught in U.S. Pat. No. 4,337,285 issued June 29, 1982, U.S. Pat. No. 4,478,903, issued Oct. 23, 1984, a composite wrapping or packaging sheet having a carbon-impregnated conductive covering layer laminated by coextruding this layer on the face of a substrate, is suggested. However, this patent does not suggest that such a coextruded laminate can be formed into a flexible bag or envelope. The coextruded composite is formed from non-flexible plastics, such as styrene and an ABS copolymer.